Field of the Invention
The present invention relates to a document reading apparatus for detecting multi-feed of a document, a control method in the document reading apparatus, and a storage medium.
Description of the Related Art
There is an image reading apparatus for conveying a document from an automatic document feeder (ADF) to read an image of the document and for detecting, using a multi-feed detection sensor such as an ultrasonic wave sensor, that multi-feed has occurred in the conveyed document.
The publication of Japanese Patent Application Laid-Open No. 2008-271537 discusses an image reading apparatus for, according to the fact that a multi-feed detection sensor has detected multi-feed of document, stopping conveyance of the document. The image reading apparatus displays a screen for allowing a user to select whether to resume reading of an image of the document or stop reading of an image of the document.
For example, to read an image of a document having two sheets on top of each other such as an envelope, the document is conveyed from an ADF. In this case, even if the document is properly conveyed, the multi-feed detection sensor detects multi-feed of the document sheets. After the conveyance of the document stops and if a succeeding document is conveyed to resume reading of an image of the document, the multi-feed detection sensor detects multi-feed of the document again.
In the image reading apparatus discussed in the publication of Japanese Patent Application Laid-Open No. 2008-271537, every time the multi-feed detection sensor has detected multi-feed of a document, the image reading apparatus waits for the user to give an instruction to resume conveyance of the document or reading of an image of the document, and then resumes conveyance of the document or reading of an image of the document. When an image of a document having two sheets on top of each other such as an envelope is read and even if the document is properly conveyed, multi-feed of the document is detected. Thus, the user needs to give an instruction to resume conveyance of a document or reading of an image of a document each time, which is cumbersome.